package com.itheima.homework3;

public class Demo3_Fibonacci {
    public static void main(String[] args) {
        int i = fibonacci(20);
        System.out.println(i);
    }
    public static int fibonacci(int n){
        if(n==1||n==2){
            return 1;
        }
        return fibonacci(n-1)+fibonacci(n-2);
    }
}
